There are a lot of different kinds of level control instruments. Below is not an exhaustive list, but we thought it'd be useful to put together a quick reference for level control options. Here's a few of the most common level control indicators we see.
Float switches
- Spherical shape.
- When the water reaches the float switch, the contact on the float signals that it has reached that level.
- On/off control - the water is either at that point or not, making this type less precise than other options.
- In trends, the level would information looks like a bar graph.
- If used as primary level control, 4-5 floats are used.
- Often used as a backup level control system with 2 floats (high and low level).
- Often higher maintenance due to grease build up.
- Inexpensive
Level Probes
- Stick like shape.
- Contacts spaced out on probe. When water reaches the contact, it signals that the water has reached that level.
- Comes in many different sizes and different amount of contacts on a probe.
- On/off control - the water is either at that point or not, making this type less precise than other options.
- In trends, the level information looks like a bar graph.
Submersible Pressure Transducers
- Sensor submerged at botton of wet well.
- Great for use in lift stations.
- Comes in different pressure sizes, such as 0-5 psi or 0-10 psi. The top psi value relates to the maximum amount of water that could be in the tank.
- Gives 4-20 mA range, so very precise.
- In trends, the level information looks like a line graph/smooth line.
Pressure Transmitters
- Sensor mounted in pressure line.
- Commonly used in water systems.
- Comes in different pressure sizes, such as 0-5 psi or 0-10 psi. The top psi value relates to the maximum amount of water that could be in the tank.
- Gives 4-20 mA range, so very precise.
- In trends, the level information looks like a line graph/smooth line.
Ultrasonic transducers
- Sensor mounted from above liquid and uses ultrasonic signal to tell level.
- Good in applications where submerged sensor not an option.
- Gives 4-20 mA range, so very precise.
- In trends, the level information looks like a line graph/smooth line.
- Watch out for foam affecting readings.